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961.
Vasantika Suryawanshi Ina N. Talke Michael Weber Roland Eils Benedikt Brors Stephan Clemens Ute Krämer 《BMC genomics》2016,17(13):1034
Background
Gene copy number divergence between species is a form of genetic polymorphism that contributes significantly to both genome size and phenotypic variation. In plants, copy number expansions of single genes were implicated in cultivar- or species-specific tolerance of high levels of soil boron, aluminium or calamine-type heavy metals, respectively. Arabidopsis halleri is a zinc- and cadmium-hyperaccumulating extremophile species capable of growing on heavy-metal contaminated, toxic soils. In contrast, its non-accumulating sister species A. lyrata and the closely related reference model species A. thaliana exhibit merely basal metal tolerance.Results
For a genome-wide assessment of the role of copy number divergence (CND) in lineage-specific environmental adaptation, we conducted cross-species array comparative genome hybridizations of three plant species and developed a global signal scaling procedure to adjust for sequence divergence. In A. halleri, transition metal homeostasis functions are enriched twofold among the genes detected as copy number expanded. Moreover, biotic stress functions including mostly disease Resistance (R) gene-related genes are enriched twofold among genes detected as copy number reduced, when compared to the abundance of these functions among all genes.Conclusions
Our results provide genome-wide support for a link between evolutionary adaptation and CND in A. halleri as shown previously for Heavy metal ATPase4. Moreover our results support the hypothesis that elemental defences, which result from the hyperaccumulation of toxic metals, allow the reduction of classical defences against biotic stress as a trade-off.962.
963.
Functional roles of Otx2 transcription factor in postnatal mouse retinal development 总被引:1,自引:0,他引:1
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Koike C Nishida A Ueno S Saito H Sanuki R Sato S Furukawa A Aizawa S Matsuo I Suzuki N Kondo M Furukawa T 《Molecular and cellular biology》2007,27(23):8318-8329
We previously reported that Otx2 is essential for photoreceptor cell fate determination; however, the functional role of Otx2 in postnatal retinal development is still unclear although it has been reported to be expressed in retinal bipolar cells and photoreceptors at postnatal stages. In this study, we first examined the roles of Otx2 in the terminal differentiation of photoreceptors by analyzing Otx2; Crx double-knockout mice. In Otx2+/-; Crx-/- retinas, photoreceptor degeneration and downregulation of photoreceptor-specific genes were much more prominent than in Crx-/- retinas, suggesting that Otx2 has a role in the terminal differentiation of the photoreceptors. Moreover, bipolar cells decreased in the Otx2+/-; Crx-/- retina, suggesting that Otx2 is also involved in retinal bipolar-cell development. To further investigate the role of Otx2 in bipolar-cell development, we generated a postnatal bipolar-cell-specific Otx2 conditional-knockout mouse line. Immunohistochemical analysis of this line showed that the expression of protein kinase C, a marker of mature bipolar cells, was significantly downregulated in the retina. Electroretinograms revealed that the electrophysiological function of retinal bipolar cells was impaired as a result of Otx2 ablation. These data suggest that Otx2 plays a functional role in the maturation of retinal photoreceptor and bipolar cells. 相似文献
964.
During mammalian development, morphogenesis of the testis requires the coordinated interplay of somatic cells to form seminiferous cords in which the primitive germ cells reside. These cords are the precursor of the functional male gonad and as such form the basis of male fertility. Cell migration during mammalian organogenesis and formation of complex tissues, such as the testis, are difficult to study in situ. Herein, we report extensive rearrangement of cells to regenerate complete functional testis tissue after implantation of isolated neonatal porcine testis cells under the skin of immunodeficient mice. Somatic cells and germ cells reorganized into structures that have remarkable morphologic and physiologic similarity to normal testis tissue, forming the endocrine and spermatogenic compartment of the testis. This unique in vivo system provides an accessible model for the study of testicular morphogenesis that could be especially useful in nonrodent species. 相似文献
965.
We isolated a novel acid-labile yellow chromophore from the incubation of lysine, histidine and d-threose and identified its chemical structure by one and two-dimensional NMR spectroscopy combined with LC-tandem mass spectrometry. This new cross-link exhibits a UV absorbance maximum at 305 nm and a molecular mass of 451 Da. The proposed structure is 2-amino-5-(3-((4-(2-amino-2-carboxyethyl)-1H-imidazol-1-yl)methyl)-4-(1,2-dihydroxyethyl)-2-formyl-1H-pyrrol-1-yl)pentatonic acid, a cross-link between lysine and histidine with addition of two threose molecules. It was in part deduced and confirmed through synthesis of the analogous compound from n-butylamine, imidazole and d-threose. We assigned the compound the trivial name histidino-threosidine. Systemic incubation revealed that histidino-threosidine can be formed in low amounts from fructose, glyceraldehyde, methylglyoxal, glycolaldehyde, ascorbic acid, and dehydroascorbic acid, but at a much higher yield with degradation products of ascorbic acid, i.e. threose, erythrose, and erythrulose. Bovine lens protein incubated with 10 and 50 mM threose for two weeks yielded 560 and 2840 pmol/mg histidino-threosidine. Histidino-threosidine is to our knowledge the first Maillard reaction product known to involve histidine in a crosslink. 相似文献
966.
Michael Watson Mónica Pérez-Alegre Michael Denis Baron Céline Delmas Peter Dov? Mylène Duval Jean-Louis Foulley Juan José Garrido-Pavón Ina Hulsegge Florence Jaffrézic ángeles Jiménez-Marín Miha Lavri? Kim-Anh Lê Cao Guillemette Marot Daphné Mouzaki Marco H Pool Christèle Robert-Granié Magali San Cristobal Gwenola Tosser-Klopp David Waddington Dirk-Jan de Koning 《遗传、选种与进化》2007,39(6):669-683
Microarrays allow researchers to measure the expression of thousands of genes in a single experiment. Before statistical comparisons can be made, the data must be assessed for quality and normalisation procedures must be applied, of which many have been proposed. Methods of comparing the normalised data are also abundant, and no clear consensus has yet been reached. The purpose of this paper was to compare those methods used by the EADGENE network on a very noisy simulated data set. With the a priori knowledge of which genes are differentially expressed, it is possible to compare the success of each approach quantitatively. Use of an intensity-dependent normalisation procedure was common, as was correction for multiple testing. Most variety in performance resulted from differing approaches to data quality and the use of different statistical tests. Very few of the methods used any kind of background correction. A number of approaches achieved a success rate of 95% or above, with relatively small numbers of false positives and negatives. Applying stringent spot selection criteria and elimination of data did not improve the false positive rate and greatly increased the false negative rate. However, most approaches performed well, and it is encouraging that widely available techniques can achieve such good results on a very noisy data set. 相似文献
967.
Ovarian development and changes in the expression of pituitary gonadotropin subunits during the reproductive cycle of female Malaysian river catfish,Hemibagrus nemurus (Valenciennes, 1840), in captivity
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968.
969.
‘Rules that apply in times of crisis’: time,agency, and norm‐remaking during Nepal's People's War
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Ina Zharkevich 《The journal of the Royal Anthropological Institute》2017,23(4):783-800
This article explores how people in the former Maoist heartland of Nepal adopted previously transgressive norms and practices during the decade of the People's War (1996‐2006). By examining the rise in practices of beef‐eating and inter‐caste commensality, this article suggests that the temporal dimension of wartime ‘when different rules apply’ was crucial in making people accept new ideas and break established norms on a scale atypical for the ‘normal’ times of peace. Analysing the agency of Maoist activists, who self‐consciously tried to implement a project of radical social transformation, and those people who were caught in the midst of the Maoist transformative endeavour, this article argues that the contours of the ‘new society’ emerged not only due to revolutionaries’ intentional actions but also because of the ‘exceptional’ nature of wartime, which forced people to radically re‐create their daily lives. By transgressing social norms, ‘ordinary’ people did not deliberately undermine the normative order, but rather responded to the constraints of wartime, when people's agency and ethical choices were mostly driven by the need to secure the survival of their families and ensure the continuity of life itself. 相似文献
970.
Daniel Langenstroth-Röwer Jörg Gromoll Joachim Wistuba Ina Tröndle Sandra Laurentino Stefan Schlatt 《Epigenetics》2017,12(7):527-539
The timing of de novo DNA methylation in male germ cells during human testicular development is yet unsolved. Apart from that, the stability of established imprinting patterns in vitro is controversially discussed. This study aimed at determining the timing of DNA de novo methylation and at assessing the stability of the methylation status in vitro. We employed the marmoset monkey (Callithrix jacchus) as it is considered the best non-human primate model for human testicular development. We selected neonatal, pre-pubertal, pubertal, and adult animals (n = 3, each) and assessed germ cell global DNA methylation levels by 5-methyl cytosine staining, and Alu elements and gene-specific methylation (H19, LIT1, SNRPN, MEST, OCT4, MAGE-A4, and DDX-4) by pyrosequencing. De novo methylation is progressively established during postnatal primate development and continues until adulthood, a process that is different in most other species. Importantly, once established, methylation patterns remained stable, as demonstrated using in vitro cultures. Thus, the marmoset monkey is a unique model for the study of postnatal DNA methylation mechanisms in germ cells and for the identification of epimutations and their causes. 相似文献